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From the U.S. Preventive Services Task Force, Agency for Healthcare Research and Quality, Rockville, Maryland.

Disclaimer: Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

Financial Support: The USPSTF is an independent, voluntary body. The U.S. Congress mandates that the Agency for Healthcare Research and Quality support the operations of the USPSTF.

Description:Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation statement on screening for breast cancer in the general population.

Methods:The USPSTF examined the evidence on the efficacy of 5 screening modalities in reducing mortality from breast cancer: film mammography, clinical breast examination, breast self-examination, digital mammography, and magnetic resonance imaging in order to update the 2002 recommendation. To accomplish this update, the USPSTF commissioned 2 studies: 1) a targeted systematic evidence review of 6 selected questions relating to benefits and harms of screening, and 2) a decision analysis that used population modeling techniques to compare the expected health outcomes and resource requirements of starting and ending mammography screening at different ages and using annual versus biennial screening intervals.

Recommendations:The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take into account patient context, including the patient's values regarding specific benefits and harms. (Grade C recommendation)

The USPSTF recommends biennial screening mammography for women between the ages of 50 and 74 years. (Grade B recommendation)

The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older. (I statement)

The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination beyond screening mammography in women 40 years or older. (I statement)

The USPSTF concludes that the current evidence is insufficient to assess additional benefits and harms of either digital mammography or magnetic resonance imaging instead of film mammography as screening modalities for breast cancer. (I statement)

The U.S. Preventive Services Task Force (USPSTF) makes recommendations about preventive care services for patients without recognized signs or symptoms of the target condition.

It bases its recommendations on a systematic review of the evidence of the benefits and harms and an assessment of the net benefit of the service.

The USPSTF recognizes that clinical or policy decisions involve more considerations than this body of evidence alone. Clinicians and policymakers should understand the evidence but individualize decision making to the specific patient or situation.

The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms. This is a C recommendation.

The USPSTF recommends biennial screening mammography for women aged 50 to 74 years. This is a B recommendation.

The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older. This is an I statement.

The USPSTF recommends against teaching breast self-examination (BSE). This is a D recommendation.

The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination (CBE) beyond screening mammography in women 40 years or older. This is an I statement.

The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of either digital mammography or magnetic resonance imaging (MRI) instead of film mammography as screening modalities for breast cancer. This is an I statement.

Figures 1 and 2 summarize the recommendations and provide suggestions for clinical practice.

Importance

Breast cancer is the second-leading cause of cancer death among women in the United States. Widespread use of screening, along with treatment advances in recent years, have been credited with significant reductions in breast cancer mortality.

Detection

Mammography, as well as physical examination of the breasts (CBE and BSE), can detect presymptomatic breast cancer. Because of its demonstrated effectiveness in randomized, controlled trials of screening, film mammography is the standard for detecting breast cancer; in 2002, the USPSTF found convincing evidence of its adequate sensitivity and specificity.

Benefits of Detection and Early Intervention

There is convincing evidence that screening with film mammography reduces breast cancer mortality, with a greater absolute reduction for women aged 50 to 74 years than for women aged 40 to 49 years. The strongest evidence for the greatest benefit is among women aged 60 to 69 years.

Among women 75 years or older, evidence of benefits of mammography is lacking.

The evidence for additional effects of CBE beyond mammography on breast cancer mortality is inadequate.

The evidence for benefits of digital mammography and MRI of the breast, as a substitute for film mammography, is also lacking.

Harms of Detection and Early Intervention

The harms resulting from screening for breast cancer include psychological harms, unnecessary imaging tests and biopsies in women without cancer, and inconvenience due to false-positive screening results. Furthermore, one must also consider the harms associated with treatment of cancer that would not become clinically apparent during a woman's lifetime (overdiagnosis), as well as the harms of unnecessary earlier treatment of breast cancer that would have become clinically apparent but would not have shortened a woman's life. Radiation exposure (from radiologic tests), although a minor concern, is also a consideration.

Adequate evidence suggests that the overall harms associated with mammography are moderate for every age group considered, although the main components of the harms shift over time. Although false-positive test results, overdiagnosis, and unnecessary earlier treatment are problems for all age groups, false-positive results are more common for women aged 40 to 49 years, whereas overdiagnosis is a greater concern for women in the older age groups.

There is adequate evidence that teaching BSE is associated with harms that are at least small. There is inadequate evidence concerning harms of CBE.

USPSTF Assessment

The USPSTF has reached the following conclusions:

For biennial screening mammography in women aged 40 to 49 years, there is moderate certainty that the net benefit is small. Although the USPSTF recognizes that the benefit of screening seems equivalent for women aged 40 to 49 years and 50 to 59 years, the incidence of breast cancer and the consequences differ. The USPSTF emphasizes the adverse consequences for most women—who will not develop breast cancer—and therefore use the number needed to screen to save 1 life as its metric. By this metric, the USPSTF concludes that there is moderate evidence that the net benefit is small for women aged 40 to 49 years.

For biennial screening mammography in women aged 50 to 74 years, there is moderate certainty that the net benefit is moderate.

For screening mammography in women 75 years or older, evidence is lacking and the balance of benefits and harms cannot be determined.

For the teaching of BSE, there is moderate certainty that the harms outweigh the benefits.

For CBE as a supplement to mammography, evidence is lacking and the balance of benefits and harms cannot be determined.

For digital mammography and MRI as a replacement for mammography, the evidence is lacking and the balance of benefits and harms cannot be determined.

Patient Population Under Consideration

This recommendation statement applies to women 40 years or older who are not at increased risk for breast cancer by virtue of a known underlying genetic mutation or a history of chest radiation.

Assessment of Risk

Increasing age is the most important risk factor for breast cancer for most women. Women without known deleterious genetic mutations (such as BRCA1 or BRCA2) may still have other demographic, physical, or historical risk factors for breast cancer, but none conveys a clinically important absolute increased risk for cancer.

Screening Tests

In recent decades, the early detection of breast cancer has been accomplished by physical examination by a clinician (CBE), by a woman herself (BSE), or by mammography. Standardization of mammography practices enacted by the Mammography Quality Standards Act have led to improved mammography quality. Clinicians should refer patients to Mammography Quality Standards Act–certified facilities, a listing of which is available at www.fda.gov/cdrh/mammography/certified.html.

Screening Intervals

In trials that demonstrated the effectiveness of mammography in decreasing breast cancer mortality, screening was performed every 12 to 33 months. The evidence reviewed by the USPSTF indicates that a large proportion of the benefit of screening mammography is maintained by biennial screening, and changing from annual to biennial screening is likely to reduce the harms of mammography screening by nearly half. At the same time, benefit may be reduced when extending the interval beyond 24 months; therefore the USPSTF recommends biennial screening.

Treatment

Effective treatments, including radiation, chemotherapy (including hormonal treatment), and surgery, are available for invasive carcinoma. Although the standard treatments women receive for ductal carcinoma in situ (DCIS) include surgical approaches as well as radiation and hormonal therapy, considerable debate exists about the optimal treatment strategy for this condition.

Considerations for Practice Regarding I Statements

Clinical Breast Examination

Potential Preventable Burden.

The evidence for CBE, although indirect, suggests that CBE may detect a substantial proportion of cases of cancer if it is the only screening test available. In parts of the world where mammography is infeasible or unavailable (such as India), CBE is being investigated in this way.

Potential Harms.

The potential harms of CBE are thought to be small but include false-positive test results, which lead to anxiety and breast cancer worry, as well as repeated visits and unwarranted imaging and biopsies.

Costs.

The principal cost of CBE is the opportunity cost incurred by clinicians in the patient encounter.

Current Practice.

Surveys suggest (1) that the CBE technique used in the United States currently lacks a standard approach and reporting standards. Clinicians who are committed to spending the time on CBE would benefit their patients by considering the evidence in favor of a structured, standardized examination (2).

Digital Mammography

Potential Preventable Burden.

Digital mammography detects some cases of cancer not identified by film mammography; film mammography detects some cases of cancer not identified by digital mammography. Overall detection is similar for many women. For women who are younger than 50 years or have dense breast tissue, overall detection is somewhat higher with digital mammography. It is not clear whether this additional detection would lead to reduced mortality from breast cancer.

Potential Harms.

The possibility of false-positive test results is similar for film and digital mammography. It is uncertain whether overdiagnosis occurs more with digital mammography than with film mammography.

Costs.

Digital mammography is more expensive than film mammography.

Current Practice.

Some clinical practices are now switching their mammography equipment from film to digital. This may curtail the availability of film mammography in some areas.

Magnetic Resonance Imaging

Potential Preventable Burden.

Studies of the use of contrast-enhanced MRI for breast cancer screening have been conducted only in very high-risk populations. In these studies, MRI detected more cases of cancer than did mammography. It is unknown whether detecting these additional cases of cancer would lead to reduced breast cancer mortality.

Potential Harms.

Contrast-enhanced MRI requires the injection of contrast material. Studies of MRI screening have shown that MRI yields many more false-positive results than does mammography. Magnetic resonance imaging has the potential to be associated with a greater degree of overdiagnosis than mammography.

Costs.

Magnetic resonance imaging is much more expensive than either film or digital mammography.

Current Practice.

Magnetic resonance imaging is not currently used for screening women at average risk for breast cancer.

Screening Mammography in Women 75 Years or Older

Potential Preventable Burden.

No women 75 years or older have been included in the multiple randomized clinical trials of breast cancer screening. Breast cancer is a leading cause of death in older women, which might suggest that the benefits of screening could be important at this age. However, 3 facts suggest that benefits from screening would probably be smaller for this age group than for women aged 60 to 69 years and probably decrease with increasing age: 1) the benefits of screening occur only several years after the actual screening test, whereas the percentage of women who survive long enough to benefit decreases with age; 2) a higher percentage of the type of breast cancer detected in this age group is the more easily treated estrogen receptor–positive type; and 3) women of this age are at much greater risk for dying of other conditions that would not be affected by breast cancer screening.

Potential Harms.

Screening detects not only cancer that could lead to a woman's death but also cancer that will not shorten a woman's life. Women cannot benefit from—but can be harmed by—the discovery and treatment of this second type of cancer, which includes both cancer that might some day become clinically apparent and cancer that never will. Detection of cancer that would never have become clinically apparent is called overdiagnosis, and it is usually followed by overtreatment. Because of a shortened life span among women 75 years or older, the probability of overdiagnosis and unnecessary earlier treatment increases dramatically after about age 70 or 75 years. Overdiagnosis and unnecessary earlier treatment are important potential harms from screening women in this age group.

Current Practice.

Studies show that many women 75 years or older are currently being screened.

Useful Resources

Other USPSTF recommendations on screening for genetic susceptibility for breast cancer and chemoprevention of breast cancer are available on the Agency for Healthcare Research and Quality Web site (www.preventiveservices.ahrq.gov).

Implementation

The Task Force on Community Preventive Services has reviewed the evidence on methods to increase breast cancer screening, including reminder systems and other interventions (3–5).

Explanation of Change in Recommendation

The 2002 USPSTF issued a B recommendation for screening mammography for women 40 years or older. However, it went on to say:

The precise age at which the benefits from screening mammography justify the potential harms is a subjective judgment and should take into account patient preferences. Clinicians should inform women about the potential benefits (reduced chance of dying from breast cancer), potential harms (for example, false-positive results, unnecessary biopsies), and limitations of the test that apply to women their age. Clinicians should tell women that the balance of benefits and potential harms of mammography improves with increasing age for women between the ages of 40 and 70 (6).

The updated USPSTF recommendation endorses this approach to deciding when to start screening. However, the current USPSTF is now further informed by a new systematic review (7), which incorporates a new randomized, controlled trial that estimates the “number needed to invite for screening to extend one woman's life” as 1904 for women aged 40 to 49 years and 1339 for women aged 50 to 59 years. Although the relative risk reduction is nearly identical (15% and 14%) for these 2 age groups, the risk for breast cancer increases steeply with age, starting in the 40s. Thus, the absolute risk reduction from screening (as shown by the number needed to invite to screen) is greater for women aged 50 to 59 years than for those aged 40 to 49 years.

The current USPSTF statement is also informed by the Cancer Intervention and Surveillance Modeling Network (CISNET) modeling studies (8) that accompany this recommendation. The Task Force considered both “mortality” and “life-years gained” outcomes. In this case, given that the age groups (40 to 49 years and 50 to 59 years) are adjacent, the Task Force elected to emphasize the mortality outcomes from the modeling studies. Of the 8 screening strategies found most efficient, 6 start at age 50 years rather than age 40 years. The frontier curves for the mortality outcome show only small gains but larger numbers of mammograms required when screening is started at age 40 years versus age 50 years.

In conclusion, the USPSTF reasoned that the additional benefit gained by starting screening at age 40 years rather than at age 50 years is small, and that moderate harms from screening remain at any age. This leads to the C recommendation. The USPSTF notes that a “C” grade is a recommendation against routine screening of women aged 40 to 49 years. The Task Force encourages individualized, informed decision making about when to start mammography screening.

A series of randomized clinical trials that would compare the results of stopping breast cancer screening at different ages (by first comparing stopping screening at age 75 years with continued screening, and then further comparing stopping screening at earlier ages, depending on the results of the first study) would be ethical and informative.

Extended follow-up of this type of study might also provide useful information about overdiagnosis in this age group. In general, more studies of overdiagnosis, including comparisons of lifetime breast cancer incidence among similar screened and unscreened women, would be helpful. Studies on overdiagnosis might also include long-term follow-up of women with probable missed cases of DCIS on the basis of microcalcifications that were missed in an earlier mammogram. Such studies could provide the percentage of these women who develop invasive breast cancer over the next 10 or more years.

Randomized clinical trials of film versus digital mammography among women with dense breast tissue, with sufficient follow-up to detect stage shifts (reductions of late-stage cancer) or decreases in clinical interval cases, would also be ethical and helpful.

Better understanding of certain facets of tumor biology is needed, particularly how age, race, breast density, and other factors may predispose certain women toward tumors with faster growth rates and greater lethality. This would improve the ability to determine at diagnosis which patients can be treated minimally.

Burden of Disease

Breast cancer is the most frequently diagnosed cancer in women in the United States, not including skin cancer, and is second only to lung cancer as a cause of cancer deaths. In 2008, an estimated 182 460 cases of invasive cancer and 67 770 cases of in situ breast cancer were diagnosed and 40 480 breast cancer deaths occurred (9). The National Cancer Institute, on the basis of Surveillance Epidemiology and End Result data, estimates the lifetime risk for a woman to develop breast cancer at 12% (10). The risk for breast cancer increases with age. The 10-year risk for breast cancer is 1 in 69 for a woman at age 40 years, 1 in 42 at age 50 years, and 1 in 29 at age 60 years (11). The incidence rate of breast cancer has increased since the 1970s; however, recent data show that this rate seems to be decreasing, both overall and on an age-adjusted basis. The incidence rate in 2003 was 124.2 per 100 000 women, a 6.7% decrease from the previous year (12). Discontinuation of hormone replacement therapy may be largely responsible for this observed decrease (12–13), although slowed growth or even a decline in screening mammography also may have contributed (14). Breast cancer mortality has been decreasing since 1990 by 2.3% per year overall and by 3.3% for women aged 40 to 50 years. This decrease is largely attributed to the combination of mammography screening with improved treatment (15).

Scope of Review

The systematic evidence review undertaken in support of this recommendation (7) addressed the efficacy of 5 breast cancer screening methods for reducing breast cancer mortality—film mammography, CBE, BSE, digital mammography, and MRI—by using published reports of randomized, controlled screening trials and specifically updated information from mammography trials among women in the age groups of 40 to 49 years and 70 years or older. Information on harms of breast cancer screening, such as false-positive test results, pain, anxiety, and biopsy rates, were sought from multiple sources, including systematic reviews, meta-analyses, and recently published literature. To assess the follow-up testing and other outcomes of a mammography screening program, the reviewers included data from the Breast Cancer Surveillance Consortium from 2000 to 2005.

In addition to the systematic review of screening tests, the USPSTF requested a report from the CISNET Breast Cancer Modeling Group to provide data from comparative decision models on optimal starting and stopping ages and intervals for screening mammography (8).

Accuracy of Screening Tests

Mammography, CBE, and BSE are recognized approaches for breast cancer screening. Since the 2002 USPSTF recommendation statement, digital (as opposed to film-based) mammography has been increasingly used, and MRI is being used with greater frequency for screening women at increased risk for breast cancer. The sensitivity of mammography screening is 77% to 95%, whereas specificity is 94% to 97% (16). Multiple factors, including age, time since last examination, breast tissue density, equipment, and the skill of the interpreting radiologist can affect sensitivity and specificity (17). A single, large comparison study of film and digital mammography (18) demonstrated similar diagnostic accuracy for the 2 methods, although digital mammography was better at detecting lesions in women who were younger than 50 years or premenopausal or had radiographically dense breasts. Studies of MRI in high-risk women without cancer (19) showed that MRI has a sensitivity of 71% to 100% and a specificity of 81% to 97%; MRI is therefore recommended by the American Cancer Society for women at high risk for breast cancer. However, no studies have been done on using MRI to screen women at average risk.

Clinical breast examination has a sensitivity of 40% to 69% and a specificity in the range of 88% to 99%. For BSE, sensitivity ranges from 12% to 41%, lower than that of CBE and mammography, and is age-dependent (16).

Effectiveness of Early Detection

The newly updated meta-analysis by Nelson and colleagues (7) confirms an earlier finding (16) that screening mammography reduces mortality. Improvements in the relative risk (RR) for death due to breast cancer for women aged 39 to 49 years and 50 to 59 years are similar at 0.85 (95% CI, 0.75 to 0.96) and 0.86 (CI, 0.75 to 0.99), respectively. An even greater improvement was found for women aged 60 to 69 years (RR, 0.68 [CI, 0.54 to 0.87]). Results were uncertain for older women, with a new report from a previously included trial with longer follow-up data showing an RR of 1.12 (CI, 0.73 to 1.72) for breast cancer death associated with screening women aged 70 to 74 years (based on a small number of participants). At the time of the previous meta-analysis, data from 2 trials showed an RR of 0.78 (CI, 0.62 to 0.99) for breast cancer death in screened women aged 65 to 74 years (16). Mortality reduction and life-years gained (8) were both considered important outcomes of screening in forming this recommendation; in the end, mortality reduction as observed in trials was the metric chosen to express the benefits of screening in each age group. Digital mammography has been shown to perform similarly to film mammography, although it has never been studied in relation to health outcomes. Magnetic resonance imaging has not been evaluated for its potential benefit in screening average-risk women. Clinical breast examination is inexpensive and easy to perform; however, few studies have compared the effectiveness of CBE with that of no screening and none has examined CBE and mammography versus mammography alone. Two large trials of teaching BSE outside the United States (7) demonstrated no mortality benefit in the intervention groups.

Potential Harms of Screening

Mammography

False-positive results are common with mammography and can cause anxiety and lead to additional imaging studies and invasive procedures (such as biopsy or fine-needle aspiration). False-positive results and accompanying additional imaging studies are more common in younger women. Biopsies may occur as a consequence of false-positive mammography results; biopsy rates are more common among older women. Anxiety, distress, and other psychosocial effects can exist with abnormal mammography results but fortunately are usually transient, and some research suggests that these effects are not a barrier to screening. False-negative results occur at a relatively low rate for all ages, but are slightly higher in women older than 70 years. Other potential harms, such as pain caused by the procedure, exist but are thought to have little effect on mammography use.

Overdiagnosis can occur when screening detects early-stage invasive breast cancer or DCIS in a woman, typically older, who is likely to die from another cause before the breast cancer would be clinically detected. Overdiagnosis can also occur in younger women if a detected DCIS or other early-stage lesion never progresses to invasive cancer. Methods for estimating overdiagnosis at a population level are not well established, and thus the proportion of all detected DCIS lesions that constitute overdiagnosis is uncertain (7). Similarly, unnecessary earlier treatment can occur at any age when screening detects a slower-growing cancer that would have eventually become clinically apparent but would never have caused death.

Radiation exposure may increase the risk for breast cancer, but usually only at much higher doses than those used in mammography, although regular mammography could contribute to cumulative radiation doses from additional imaging for other reasons (7).

Digital Mammography and Magnetic Resonance Imaging

Digital mammography can be expected to have harms similar to those of film mammography. No studies have evaluated MRI screening of average-risk women; in theory, because MRI could be considerably less specific than mammography screening, it could potentially be associated with higher biopsy rates and greater degrees of overdiagnosis if used in low-risk populations.

Clinical Breast Examination

A theoretical harm of CBE is that its lower specificity than that of mammography may result in more women undergoing biopsy. Few data are available to evaluate harms associated with CBE.

Breast Self-Examination

One study indicated that anxiety was not a concern with BSE. The 2 available trials (20–21) indicated that more additional imaging procedures and biopsies were done for women who performed BSE than for control participants.

Estimate of Magnitude of Net Benefit

In 2002, the USPSTF concluded that there was fair evidence that mammography screening every 12 to 33 months could significantly reduce breast cancer mortality. The evidence was strongest for women aged 50 to 69 years, with weaker evidence supporting mammography screening for women aged 40 to 49 years. Since that recommendation, 1 new trial and updated data from an older study have been published that specifically address screening in women in the younger age group. These findings were combined in an updated meta-analysis, which resulted in an RR for breast cancer death of 0.85 (CI, 0.75 to 0.96; 8 trials) and a number needed to invite for screening of 1904 (CI, 929 to 6378) to prevent 1 breast cancer death in women aged 39 to 49 years. A meta-analysis of 6 trials among women aged 50 to 59 years and 2 trials among women aged 60 to 69 years provided pooled RRs for breast cancer death in the screened group of 0.86 (CI, 0.75 to 0.99; number needed to invite, 1339 [CI, 322 to 7455]) and 0.68 (CI, 0.54 to 0.87; number needed to invite, 377 [CI, 230 to 1050]), respectively. Only 1 study provided data on women older than 70 years, yielding an RR of 1.12 (CI, 0.73 to 1.72), although an RR of 0.78 (CI, 0.62 to 0.99) was found for women aged 65 to 74 years by combining the results of 2 studies used in the 2002 review.

A decision analysis performed for the USPSTF projected that biennial screening produced 70% to 99% of the benefit of annual screening, with a significant reduction in the number of mammograms required and therefore a decreased risk for harms. Screening between the ages of 50 and 69 years produced a projected 17% (range, 15% to 23%) reduction in mortality (compared with no screening), whereas extending the age range produced only minor improvements (additional 3% reduction from starting at age 40 years and 7% from extending to age 79 years) (8).

The USPSTF noted with moderate certainty that the net benefits of screening mammography in women aged 50 to 74 years were at least moderate, and that the greatest benefits were seen in women aged 60 to 69 years. For women aged 40 to 49 years, the USPSTF had moderate certainty that the net benefits were small. Because of the uncertainties related to harms of screening, particularly overdiagnosis, and the near total lack of trial data for older women, the USPSTF had low certainty about the net benefits of screening mammography for women 75 years or older.

How Does Evidence Fit With Biological Understanding?

Current knowledge about the development of breast cancer is limited. The effectiveness of screening mammography seen in trials presumably results from the early detection of smaller, earlier-stage tumors, which are more responsive to available treatments. Although the most common breast cancer occurs in the epithelial cells that line the duct system of the gland (ductal carcinoma), the sequence of development of invasive cancer is not entirely known. For example, DCIS does not always represent a precursor to invasive ductal cancer. Studies of women with untreated DCIS showed progression to invasive disease in half or fewer of the cases. Because DCIS is often found only by mammography, its incidence has increased steadily since the advent of widespread screening mammography. In 1983, 4900 cases of DCIS were diagnosed; by 2008, that number was expected to be 67 770 (22). Because the likelihood that DCIS will progress to invasive cancer is unknown, surgical removal—with or without adjuvant treatment—may represent overdiagnosis or overtreatment. Lobular carcinoma in situ, in contrast, is not considered a true precursor lesion but connotes a higher risk for subsequent invasive lobular or ductal cancer in either breast. Lobular carcinoma in situ is often multifocal, appearing in several distinct locations. Knowledge of what determines the rapidity with which invasive cancer can spread (tumor characteristics, host factors, hormonal triggers) is limited (23). Because of these elements of biological uncertainty, it is clear that lesion sensitivity alone is not a sufficient metric for assessing effectiveness of new screening methods (24).

This recommendation updates the 2002 recommendation by providing specific recommendations for mammography screening by age. The previous recommendation statement recommended screening mammography every 1 to 2 years for all women older than 40 years. The USPSTF now recommends against routine screening of women aged 40 to 49 years (C recommendation), recommends biennial screening mammography for all women aged 50 to 74 years (B recommendation), and provides an I statement regarding screening of women older than 75 years. The USPSTF now recommends against teaching BSE (D recommendation), replacing the previous statement of insufficient evidence. The evidence for CBE continues to be assessed as insufficient. Digital mammography and MRI as screening tools were not addressed in the 2002 recommendation statement; the USPSTF concludes that the evidence is insufficient to assess the harms or benefits of these methods for screening.

Numerous organizations have provided breast cancer screening recommendations. These recommendations are summarized below. All recommendations are for women not at increased risk for breast cancer.

In 2003, the American Cancer Society recommended annual mammography beginning at age 40 years, annual CBE after the age of 40 years (25). It does not recommend MRI for women at average risk for breast cancer and states that there is insufficient evidence to recommend BSE.

The American Medical Association, in 2002 (26), and the National Comprehensive Cancer Network, in 2009 (27), have made recommendations similar to those of the American Cancer Society, except for the inclusion of a positive recommendation for BSE.

The American Academy of Family Physicians has endorsed the USPSTF recommendation on breast cancer screening in the past (28). The American College of Physicians recommended in 2007 that screening mammography decisions in women aged 40 to 49 years should be based on individualized assessment of risk for breast cancer; that clinicians should inform women aged 40 to 49 years about the potential benefits and harms of screening mammography; and that clinicians should base screening mammography decisions on benefits and harms of screening, as well as on a woman's preferences and breast cancer risk profile (29).

According to the Canadian Task Force on Preventive Health Care in 2001:

Current evidence … does not suggest the inclusion of the manoeuvre in, or its exclusion from, the periodic health examination of women aged 40–49 years at average risk of breast cancer (grade C recommendation). Upon reaching the age of 40, Canadian women should be informed of the potential benefits and risk of screening mammography and assisted in deciding at what age they wish to initiate the manoeuvre (30).

In 2003, the American College of Obstetrics and Gynecology recommended mammography every 1 to 2 years for women aged 40 to 49 years and annually after the age of 50 years (31). It recommended CBE for all women and noted that BSE can be recommended.

In 2009, the World Health Organization recommended mammography every 1 to 2 years for women aged 50 to 69 years, but does not recommend CBE or BSE (32).

Addendum: On 4 December 2009, the U.S. Preventive Services Task Force (USPSTF) voted unanimously to update the language of its recommendation regarding women younger than 50 years to clarify its original and continued intent. The USPSTF omitted the first sentence of the recommendation. The recommendation for women younger than 50 now reads: “The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.”

Qaseem A,Snow V,Sherif K,Aronson M,Weiss KB,Owens DK,Clinical Efficacy Assessment Subcommittee of the American College of Physicians. Screening mammography for women 40 to 49 years of age: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2007; 146:511-5. PubMed

Qaseem A,Snow V,Sherif K,Aronson M,Weiss KB,Owens DK,Clinical Efficacy Assessment Subcommittee of the American College of Physicians. Screening mammography for women 40 to 49 years of age: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2007; 146:511-5. PubMed

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As lead mammographer in my hospital, I can tell you that if we stop screening 40-50 yr. olds we will experience a giant step backward in detecting early cancer. Many of the cases that are detected at in situ or stage 1 will be seen later in her life as Stage 3 or 4 ; not much prevention there. I am sure women are much smarter than that. Shame on giving in on Government health care ideas.

Conflict of Interest:

None declared

Re:The 40-50 age group.

Posted on
November 18, 2009

philip s walter

No Affiliation

Conflict of Interest:
None Declared

This is one problem with what we do on a daily basis. Evidence has to be separated from the intuitive reactions we have. The response from the radiologist implies that he knows that all of the tumors he finds will have an impact on the life of the patient.

Conflict of Interest:

None declared

Re:The 40-50 age group.

Posted on
November 18, 2009

Victoria L. Seewaldt

Duke University

Conflict of Interest:
None Declared

The U.S. Preventive Services Task Force (USPSTF) recently recommended against routine mammographic screening in women ages 40-49 (1). The recommendation was based on the relative probability of unscreened women dying of breast cancer and the reduction in mortality provided by mammographic screening. Based on these studies the USPSTF issued a blanket recommended against routine screening mammography in all women 40-49 years -of-age (1).

Lacking from the USPSTF study is evidence to support a reduction in mammography screening in African American and Latino women who are less than 50 years-of-age (1). The USPSTF study analyzed the risk/benefit mammography as a function of a woman's age but did not consider the potential contributions of race and ethnicity (1). Investigators did not state the racial and ethnic composition of study participants and there was no analysis of the risk/benefit of mammography in African-American and Latino women (1).

It is concerning that USPSTF issued a one-size-fits-all blanket breast cancer screening recommendation without considering whether the recommendation is appropriate for all women.

Our current recommendations for mammographic screening are based on studies in European, European-Canadian and European-American women. Eight reported randomized trials studied mammography's effectiveness in the United States, Sweden, Canada, and the United Kingdom (for a review, see reference 2). These studies balance the relative contributions of mammographic density (sensitivity and specificity of mammography) and the death rate from breast cancers (2). To our knowledge, there has been no large-scale analysis of the effectiveness of mammographic screening in African-American and Latino women.

Studies of mammographic screening in women ages 40-49 are complex because younger women have a lower incidence of breast cancer, denser breast tissue (which can lower sensitivity), and, on average, faster growing, biologically aggressive cancers. Relative to European-American women, African-American women have lower breast density, faster growing cancers, and a higher likelihood of dying from breast cancer (3-5). Since the death rate from breast cancer in African-American women is higher and mammographic density is typically lower, it is likely that the benefit from mammographic screening will be higher in African-American, and perhaps Latino women, than in European-American women.

So where's the evidence to recommend against routine mammography screening of African American and Latino women under 50 years-of-age?

We agree with the USPSTF that there is a need for change. But the change we call for is an end to one-size-fits-all recommendations and inclusion of African-American and Latino women in clinical trials testing the benefit of mammographic screening.

Conflict of Interest:

None declared

The Editors' Response

Posted on
November 20, 2009

The Editors

Annals of Internal Medicine

Conflict of Interest:
None Declared

"In response to media reports that imply otherwise, Annals of Internal Medicine did not schedule the publication of the US Preventive Services Task Force recommendations about breast cancer screening to coincide with a particular date or event. The background papers (which underwent several rounds of revision over about 5 months based on independent peer review comments and Annals' statistical editor's comments) and the recommendation statement were all in final, accepted form by September 10, 2009. Annals scheduled them to appear in the next available print issue, which was the November 17th issue. Our routine print production process takes about 2 months from final acceptance to print." The Editors

Conflict of Interest:

None declared

The USPSTF Recommendations Are Not Scientifically Based - Underestimate the Benefit of Mammography and Admit That Lives Will Be Lost Unnecessarily

Posted on
November 20, 2009

Daniel B. Kopans

Harvard Medical School/Massachusetts General Hospital

Conflict of Interest:
None Declared

The US Preventive Services Task Force (USPSTF) acknowledges that mammography screening, beginning at the age of 40, significantly decreases breast cancer deaths. Their guidelines, however, ignore the science and direct measurements of benefit to limit access to screening.

1. None of the parameters of screening change abruptly at the age of 50 or any other age (1). The age of 50 is an arbitrary threshold. 2. The USPSTF correctly used the randomized, controlled trials (RCT) as scientific proof of benefit. However, since the RCT did not stratify by risk, there is no proof that screening based on risk will save lives, and no scientific support for recommending screening based on risk (2). Screening only women at high risk will miss the 75-90% of breast cancers that occur in women who are not at high risk. 3. The USPSTF chose the lowest possible reduction in breast cancer deaths (15%), unaware of the fact that the RCT underestimate benefit. Women allocated to be screened who refuse the invitation, and die of breast cancer, are still counted as having been screened (non-compliance). Women allocated to be controls whose lives are saved by mammograms that they obtain outside the trial, are still counted as unscreened controls (contamination). 4. The USPSTF recognizes a 30 % decrease in breast cancer deaths in the U.S. since 1990 but ignore it, and ignore the 40% decrease in breast cancer deaths reported in Sweden (3), predominantly due to screening, that applies to women in their forties. 5 Ignoring direct data they used a 15% reduction in deaths and estimated 1300 women needed to be screened (NTS) to save one life was a reasonable number to support recommending mammography. They would deny screening to women ages 40-49 because they estimated their NTS was 1900. In reality there is 30-40% decrease in deaths for women in their forties so, using their formula, the NTS is 950-705 for women in their forties putting them well below the threshold. 6 Most false positive mammograms are easily resolved with a few extra pictures. Most biopsies are needle biopsies. Over treatment is not the fault of mammography and should be addressed to the oncologists. 7. The Task Force admits that lives will be lost by increasing the time between screens to two years.

Before denying women access to screening, anyone advising women needs to be aware of the facts.

References

1. Kopans DB. Informed decision making: age of 50 is arbitrary and has no demonstrated influence on breast cancer screening in women. Am J Roentgenology 2005;185:177-82

Conflict of Interest:

The USPSTF Recommendations should consider quality of life for breast cancer patients

Posted on
November 22, 2009

Cicero Urban

Breast Unit HNSG and Positivo University, Curitiba, Brazil

Conflict of Interest:
None Declared

The US Preventive Services Task Force (USPSTF) acknowledges that mammography screening, beginning at the age of 40, is not indicated for lower risk patients. Their guidelines, however, ignore the fact that breast cancer screening nowadays has two aims, from our point of view as breast surgeons. The first, of course, is regarding breast cancer deaths, which was discussed and can be easily calculated. But, the second one is related to the benefits of earlier diagnosis to breast surgery. We can preserve the breast and the axilla in most of patients with their breast cancer diagnosed in screening programs. Our current index of breast conservation surgery in a well selected population of brazilian patients in Curitiba (south of Brazil) who have access to screening today, is over 60%. Most of them (about 80%) had no axillary dissection, since the sentinel node was negative. These facts are directly related to quality of life in this group of patients. So there is a strong relation between screening and more conservative surgeries. I think that we can change our current recommendations in the future only if we consider the benefits to breast cancer patients in both aims. Mortality cannot be the only tool to be considered in the future guidelines. To save lifes is important, but to preserve quality of life is our current aim too in times of sentinel node and oncoplastic surgery.

The USPSTF recommendation that women in the age group 40-50 not have screening mammograms comes from poor judgment about breast cancer data and clinical understanding of breast cancer. Coupling this recommendation to the recommendation that women in this age group not examine themselves clearly indicates that the panel members have limited understanding of breast cancer detection. To be sure there is no good evidence that breast self-examination lowers the risk breast cancer death. However, by limiting themselves to the impact of self-examination on mortality, they failed to address a second question raised by their recommendation that these women not have mammographic screening. Who is it that most often diagnoses breast cancer in the age group of 40-50 years? In unscreened women it is overwhelmingly the women themselves. If one follows the USPSTF recommendations that women in this age should not be screened and should not perform self-examination, how are breast cancers to be diagnosed? Certainly this will not come from annual clinical breast examination.

Conflict of Interest:

Although the Task Force breast cancer screening recommendations are meant to provide guidance to clinicians and their patients, these and many other Task Force recommendations are also released in a public health arena and because they address entire or large segments of a population may have unintended or unforeseen public health impacts. Unfortunately, the current research and communications methodologies of the Task Force seem not to take this into account.

For example, the recommendation against clinicians teaching Breast Self Examination (BSE) I assume was related to a particular form of BSE. This appears to be based on several assumptions that fail to take into account the possible impact of this recommendation. First, it assumes that most such education occurs through interactions with clinicians. While the recommendation is only to clinicians, the Task Force fails to explain how this might or might not apply to other settings or persons,for example, health educators, public health departments. Nor does the lack of specificity regarding this recommendation account for the possibility that women be taught how to be more self aware of and how to conduct self examinations of their breasts for other reasons.

In addition, the language utilized in the recommendations indicates that the only concern is for clinicians and their patients. However, the recommendations are also widely disseminated in the media to populations of women who do not have health care coverage or clinicians they interact with on a regular basis - or if they do, only in emergency situations. One could easily hypothesize that the recommendations as perceived by these populations could have the unintended effect of not only decreasing use of breast cancer detection services (including public health services) but also conveying the impression that these are not important issues for those without regular health care. Furthermore, there is little consideration about what the impact on other health behaviors may be at a time when the entire health community is trying to get people to be more aware of and take a more active role in their health and health behaviors,and to shift towards prevention and early intervention before tertiary interventions may be required. While the Task Force properly tries to address one clinical issue at a time, it operates in an arena in which clinical and public health concerns and impacts naturally intermingle, where individuals apply what they have learned about one health behavior to another. As much as it may assume otherwise, the recommendations go not only to clinicians who have patients but to many who might be patients but in reality have little regular interaction with clinicians, and to non-clinicians who regularly address the same or similar health concerns with the patients of others.

It may be an overstatement that the Task Force exemplifies the unfortunate, and I think harmful, gap between our health care/clinical and public health systems. However, the Task Force format needs to be revised so that research and data from the public health arena be factored in and that there be recognition that the recommendations also have public health connotations which must also be factored in when making and releasing clincal recommendations. Richard Yoast, PhD

Conflict of Interest:

None declared

Distressing Internal Inconsistencies

Posted on
November 25, 2009

James F. Ruiz

Woman's Hospital

Conflict of Interest:
None Declared

A primary source motivating the USPSTF to alter guidelines states that "conclusions about the optimal starting ages for screening depend more on the measure chosen for evaluating outcomes. If program benefits are measured in life-years, the measure most commonly used in cost- effectiveness analysis, then our results suggest that initiating screening at age 40 years saves more life-years... Starting annual screening at age 40 years (vs. 50 years) and continuing annually to age 69 years yields a median of 33 (range, 11 to 58) life-years gained per 1000 women screened. If the goal of a screening program is to efficiently maximize the number of life-years gained, then the preferred strategy would be to screen biennially starting at age 40 years (1)."

The USPSTF proceeds to ignore these comments to state "given that the age groups (40 to 49 years and 50 to 59 years) are adjacent, the Task Force elected to emphasize the mortality outcomes from the modeling studies." However, the USPSTF fails to describe how "adjacency" of the two age groups leads one to conclude that mortality outcomes is a better measure than life years gained. Further, the USPSTF does not counter the claim by their reference source that life years gained is "the measure most commonly used in cost-effective analysis."

Nelson's review, upon which the USPSTF relied to change their recommendations, states that "harms of mammography screening have been identified, but their magnitude and effect are difficult to measure. Mammography screening at any age is a tradeoff of a continuum of benefits and harms. The ages at which this tradeoff becomes acceptable to individuals and society are not clearly resolved by the available evidence (2)." However, the USPSTF chooses to emphasize the adverse consequences for most women and classifies harms for all age groups as "moderate."

The task force identifies false positives as the major harm in the younger age group. The task force indicates that it requires 565 more mammograms to save a life in the 40-49 year age group as compared to the 50-59 year group. Schell, et al, in evaluating the recall rate for 545,505 examinations in women aged 40-49, found that the rate is on the order of 9% which would lead to a "harm" of approximately 51 instances of additional views and/or ultrasound, 5 percutaneous biopsies under local anesthesia and the discovery of one cancer (at a rate of 3 cancers/1000 mammograms)(3). In order to conclude that the harm overshadows the life saved, the task force must find that the value of a human life is something less than the combined negative value of 616 imaging exams, 5 biopsies under local anesthesia, and the discovery of one new cancer.

In the newly passed Senate health reform bill, the USPSTF has been given a prominent role in determining what kind of care will and will not be allowed in a health care system. Under the new administration, this first effort by the USPSTF does not inspire confidence.

The US Preventive Service Task Force (USPSTF) revised recommendations on mammography have understandably stirred fierce debate. The research cited by USPSTF in support of their recommendation for women in their 40's seems compelling.

We assume in our calculation that the average cost of a mammogram is $250, about 1% of those screened will need a biopsy at an average cost of $1,000, and about 10% will need some other less expensive testing. If indeed 1,900 women in their 40's have to be screened annually for a decade to avert one breast cancer death, the associated cost comes to approximately $5 million.

The USPSTF revised guidelines recommend against performing mammography on women in their 40's on a population basis. However, for those in their 40's at high risk, they recommend mammography on a case by case basis in consultation with the physician.

Every penny of the $5 million will be well-spent if the one breast cancer death averted is of my 45-year old daughter with no known risk factor. That is where the debate gets personal and emotional- an area where science, data, and analyses become irrelevant. And, that is where the debate gets political, seemingly making all the science, all the data, and all the analyses irrelevant.

Somewhere, somehow, someone must find a middle ground so we as a society can make efficacious use of a viable early detection method for averting breast cancer deaths. It also behooves us as a society to look into other ways to avert breast cancer deaths, such as primary prevention using dietary modification. Perhaps the policy makers in addition to early detection can play a proactive role in prevention, providing a multi- pronged strategy to fight breast cancer mortality.

Conflict of Interest:

None declared

Re:The 40-50 age group.

Posted on
November 25, 2009

Vickie L Ledford

Murphy Medical Center

Conflict of Interest:
None Declared

I can not believe this is happening!! We have come so far with our outreach to women everywhere to encourage them and assure them that early detection was the best protection to keep from dying with breast cancer. I have been a mammographer for 15 years and I have too many memories of young women in their 40's being diagnosed with breast cancer. If these women waited to come in when they were 50 the cancer could have spread to their lymph nodes and would be more complex to treat. I don't know what these people were thinking when they came out with this recommendation. Mammographers need to continue to encourage women not to wait until their 50 to get a mammogram.

Mammography Screening Guidelines

Posted on
December 3, 2009

Colin B. Begg

Memorial Sloan-Kettering Cancer Center

Conflict of Interest:
None Declared

TO THE EDITOR: In their recent evaluation of mammography, the US Preventive Services Task Force recommends screening for breast cancer bi- annually starting at age 50 (1). The Task Force has stressed that this recommendation depends solely on the trade-off between medical benefits and harms, with no consideration of costs. Editorials in both the Wall Street Journal (2) and the New England Journal of Medicine (3), however, suggest that the recommendation was in fact motivated by cost considerations. A careful examination of the data analyses by Mandelblatt et al. (4), presented in support of the recommendations, would appear to confirm the view that costs were indeed pivotal in informing the Task Force recommendation.

The Task Force states that its recommendation involves trading off the mortality benefit of screening against medical "harms" such as provoked anxiety, the adverse consequences of false positive tests including unnecessary biopsies and treatment, and the adverse effects of "over-diagnosis". But how did they use the evidence about these effects to reach their recommendation? There are no analyses in the report nor in the supporting articles (4,5) that simultaneously consider both benefits and harms and that lead directly to the specific recommendation to begin screening at age 50, and to do it bi-annually. The only analysis provided that aligns clearly with the Task Force recommendation is the analysis displayed in the Figure in Mandelblatt et al. (4) This Figure presents the results from independent analyses by six investigative groups of the projected mortality reduction for a range of screening strategies, covering various starting ages, and including options to screen annually or bi-annually. The critical feature of these analyses is that the population mortality benefit is contrasted solely with the numbers of mammograms required, a surrogate for resource utilization, and thus for costs. The authors do not utilize "harms". These analyses search for an optimal strategy at the point where the graphs plateau, representing a point of diminishing returns from additional screening. Bi-annual screening strategies starting at age 50 are close to the "optimal" inflection point in all 6 of these analyses, and this would appear to be the crucial finding that motivated the Task Force recommendation. The number of mammograms in these analyses does not represent "harm". Rather, it is a measure of the societal investment in mammography, i.e. the societal cost. In other words, this is, in effect, a thinly disguised assessment of cost relative to effectiveness, something most experts would label a cost-effectiveness analysis.

Conflict of Interest:

Dept. of Health Behavior and Health Education, UNC Gillings School of Global Public Health

Conflict of Interest:
None Declared

Two recent U.S. Preventive Services Task Force (USPSTF) statements on screening for breast cancer identify harms of false-positive mammography screening test results, including psychological distress (1,2). Unfortunately, the reports drift away from published evidence about psychological distress from false-positive mammograms. The summary report dismisses the problem: "Anxiety, distress, and other psychosocial effects can exist with abnormal mammography results but fortunately are usually transient (1)." We believe this statement mischaracterizes the empirical literature, and indeed what the USPSTF reports to an extent in its own detailed concurrent report (2), which more correctly states that "False-positive mammography results had no consistent effect on most women's general anxiety and depression but increased breast cancer specific distress, anxiety, apprehension, and perceived breast cancer risk for some (2)." This statement is consistent with our own recent research where we found that false-positive mammography results cause small but reliable elevations in breast cancer-specific distress (3).

The USPSTF summary also comes to a different conclusion about transience of the effects of false-positive mammograms (1,2) than two previous systematic reviews (4,5). Brett et al. state that "women who have further investigations following their routine mammogram experience significant anxiety in the short-term, and possibly in the long-term (4)." Brett et al. did not emphasize the transience of false-positive's effects as a general finding. Similarly, our own systematic review concluded that the effects of false-positive mammography results endure over the long-term, well after cancer has been ruled out (5). We believe the correct conclusion is that false-positive mammography results cause small but reliable distress that endures for months and years.

Conflict of Interest:

Division of Cancer Epidemiology and Genetics, National Cancer Institute

Conflict of Interest:
None Declared

The U.S. Preventive Services Task Force recommended "against routine screening mammography in women aged 40 to 49 years," writing that the decision should be based on "patient context, including the patient's values regarding specific benefits and harms." These criteria do not explicitly include risk assessment. Indeed, the report (1) seems to dismiss risk assessment based on "demographic, physical or historical risk factors for breast cancer", stating that "none conveys clinically important absolute increased risk for cancer."

Although age is the most important risk factor over long age intervals, it is not as important as other risk factors over the age range 40 to 50 years. In 1998, Gail and Rimer (2) suggested that a woman in her forties should consider mammographic screening if her absolute risk was as great as that of a fifty year old women without other risk factors, because benefits are thought to outweigh risks for such a fifty year old woman, and, as argued in (2), the same should be true for a younger woman with comparable risk. The ratio of incidence rates of a fifty year old white woman with no risk factors to a forty year old white women with no risk factors is 2.46 (2). If the forty year old has risk factors that increase her risk at least 2.46 times above baseline, she has at least the absolute risk of the fifty year old. Many risk factors, such as two affected first-degree relatives, atypical hyperplasia, and at least 75% dense tissue on a mammogram have relative risks that exceed 2.46, as do many combinations of weaker risk factors (2, 3). For a 48 year old woman, risk factors need to increase baseline risk by only 6% to put her at the risk of a 50 year old with no risk factors (2).

Recent data (1) that screening reduces breast cancer mortality by 15% in women aged 39-49 and by 14% in women aged 50-59 only strengthen arguments (2) that a woman in the age range 40-49 years with the same absolute risk as a fifty year old woman has a similar ratio of benefits to adverse effects, such as false positive results requiring further evaluation. Thus, risk factors in addition to age should be considered when counseling a woman in her forties whether or not to have screening mammograms. Of course, "the patient's values regarding specific benefits and harms" should also be considered, as recommended by the Task Force (1).

Conflict of Interest:

University of Turku Faculty of Medicine and Turku University Hospital, Turku, Finland

Conflict of Interest:
None Declared

The data search for published evidence from the RCTs used by the USPSTF ended in December 2008. In June 2009 Holmberg et al. (1) published a review of the data from the Swedish Two-County Trial, which showed that the methodology used in the previous overview (2) "resulted in a reduction of the estimate of the effect of screening." Data from this previous overview (2) were used for both the 2002 and 2009 USPSTF evaluations. Although this latest Swedish overview (1) did not present results specific to age categories, the material is available for such an analysis. It is unfortunate that none of the members of the USPSTF were aware of these recently revealed flaws in their database at the time when they were in the lengthy process of deciding that the benefits of mammography screening were less than previously calculated. A more concerted effort to communicate with individuals currently working with breast cancer screening could easily have brought this newer information to their attention.

The USPSTF evaluation (3) and supporting articles are plagued with ambiguity over the use of the terms "screen" and "screening" when used alone or in conjunction with the term "mammography." Whereas the evidence of benefit has been drawn exclusively from "intention to treat" publications, the numerical conclusions have been directly applied by the USPSTF to the case of the individual woman seeking advice from her physician. If the USPSTF evaluation is taken at face value, women will be told the estimated benefit of receiving an invitation to participate in a mammography screening program, a benefit considerably lower, by a factor of approximately 1.4, than the benefit of her actually getting mammograms (4).

The harms, on the contrary, are not calculated on an "intention to basis," so the USPSTF has introduced a considerable bias into their benefit/risk calculations.

The USPSTF purports to determine, in its own words,"benefits...potential harms...and limitations of the test"(3)." The additional benefits of actually getting a mammogram have been measured in Sweden using the ongoing service screening programs (5), and results specific for women aged 40-49 have been submitted for publication. It does not appear to make good sense for the USPSTF to intentionally ignore such publications when attempting to answer their own question, since the analysis of benefit is jeopardized by exclusive reliance upon historic RCT data that were designed to answer a different question.

Conflict of Interest:

The Social Context and Values Behind the Breast Cancer Screening Controversy

Posted on
January 10, 2010

Anita Ho

Centre for Applied Ethics, University of British Columbia

Conflict of Interest:
None Declared

Regarded by many medical professionals as a premier source of information on preventive services (1), the US Preventive Services Task Force (USPSTF) was blind-sided by the recent controversy regarding its recommendation against routine screening mammography for asymptomatic women under the age of 50 (2). While the evidence-based panel prides itself on being independent of advocacy groups or managed care organizations, the controversy can be better understood if we consider the socio-political context of women's health and health-care reform. Historically, women have significantly less access to some of the major diagnostic and therapeutic interventions compared to men (3), are more likely to delay or go without necessary medical care, and express more concerns about the quality of health care they receive (4). The panel's recommendations may have prompted many to perceive, rightly or wrongly, the guidelines to be a setback in promotion of women's health.

In the midst of health-care reform discussions, the public's response may also reflect its scepticism of scientists' claim of value neutrality in evidence-based medicine and their social authority based therein. After all, even if scientific evidence is the most important factor in the panel's recommendation, what conditions are considered to create a large enough burden of suffering for society to warrant the USPSTF's investigation is partly a value judgment (5). As the USPSTF's ratings influence insurance coverage of various preventive services, the public's flat-out rejection of the panel's conclusion may be a result of its distrust in the social authority of expert opinion, confusion about the panel's decision-making process, and concerns about how rationing and funding priorities are determined by these experts.

In responding to accusations that their recommendations were politically and economically driven, the Task Force adamantly denied any financial considerations. Instead of convincing the public of its neutral stance, the USPSTF may have inadvertently perpetuated the impression that financial considerations in health care are always illegitimate. As the country continues its debate on health-care reform, the Task Force and government officials may want to use this controversy as a new opportunity to facilitate more informed and responsible discussions among citizens regarding health-care program planning and funding. Rather than simply denying that economic or social context plays any role in scientific review, it may be more fruitful for the panel to clearly explain what values were part of the consideration, and furthermore, how such values were chosen, and why such values were appropriate in determining their guidelines.

Acknowledgment

I would like to thank Dave Unger, MD, and Suze Berkhout, PhD(c), for their critical and constructive comments on an earlier draft.

References

1. Eisenberg JM, Kamerow DB. The Agency for Healthcare Research and Quality and the U.S. Preventive Services Task Force: Public support for translating evidence into prevention practice and policy. Am J Prev Med 2001;20(3S)1-2.

Conflict of Interest:

Screening for breast cancer: following the analysis conducted by the U.S. Preventive Services Task Force

Posted on
July 16, 2010

Saika Kumiko

Center for Cancer Control and Information Services, National Cancer Center

Conflict of Interest:
None Declared

Background

In 2009, the U.S. Preventive Services Task Force (USPSTF) recommended that the decision to start regular screening mammography (SC. MMG) before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms (1, 2). As a metric, they calculated the number needed to invite (NNI) to screening to prevent 1 death from breast cancer by a meta-analysis of several trials previously published (3). They concluded that the net benefit is smaller for women aged 40 to 49 years with a larger NNI compared to the value for women aged 50-59. However, they did not consider different follow-up periods when comparing NNI by age group. For women aged 40 to 49 years, the average follow-up varied from 10.7 to 16.8 years in 8 trials included in the meta-analysis, while follow-up varied from 12.9 to 18.1 years for women aged 50-59 years in 5 trials and from 14.3 to 15.5 years for women aged 60-69 years in 2 trials. Shorter follow-up periods for women aged 40-49 will lead to lower cumulative mortality, which results in an overestimation of NNI.

Objective

We aimed to estimate NNI adjusted by the follow-up period in each available study in order to compare NNI between different age groups.

Methods and Findings We estimated the NNI by applying similar methods and including similar studies to those used in the USPSTF (3). A meta-analysis of mammography trials was conducted to estimate the pooled relative risk (RR) from a random-effect model under a Bayesian analysis using the WinBUGS package (4). We included 8, 5, 2 and 1 trials for women aged 40-49, 50-59, 60-69 and 70-74 years, respectively. The NNI for screening to prevent 1 death from breast cancer reported by USPSTF was defined as the inverse of the absolute risk reduction. Here, the risk was the mortality rate during the follow-up period (death/person). In taking into account the follow-up period of studies, the estimates of NNI were calculated using the mortality rate per year (death/person-year). The estimated NNI was that based on a one-year follow-up. Thus, when we compared the NNI on the assumption that the follow-up period was x years, the estimated NNI was divided by x. In this study we tried to estimate the NNIs on the assumption of 10-year, 15-year and 20-year follow-up period.

The pooled RRs and NNIs for reducing breast cancer mortality in the USPSTF report, and our estimates calculated using the same condition are shown in Table 1. Pooled RRs with adjustment for the follow-up period were similar for all age groups. On the contrary, the NNIs were different depending on the assumed follow-up periods, i.e. 10-years, 15-years, and 20-years. On the assumption of a 10-year follow-up, the NNIs for women aged 40-49 and 50-59 were estimated to be 2399 (CI, 1195 to 8550) and 1708 (CI, 452 to 10215), respectively. The longer the assumed follow-up period, the smaller the estimates of NNIs for all age groups. More importantly, the differences in NNIs between women aged 40-49 and 50-59 were smaller in our analysis than those from the USPSTF report.

Discussion

When comparing NNIs, the follow-up period directly affects the results. The NNIs are necessarily greater in shorter follow-up period, which means the NNI can be overestimated for younger age group with relatively shorter follow-up periods if not adjusted for the follow-up. The recommendations for mammography screening by USPSTF stated that an NNI of 1904 for women aged 40-49 years was too high, yet an NNI of 1339 for women aged 50-59 years was adequate (2). However, when we adjusted for the follow-up period of the trials, the estimated NNIs for women aged 40-49 were 1599 with a 15-year follow-up and 1199 with a 20-year follow-up. Whatever the conclusion, it should not be based on biased estimates of NNIs for reducing breast cancer mortality by age group.

Supplements

Recommendation Summary

Original Version (PDF)

Summary for Patients

The summary below is from the full reports titled “Screening for Breast Cancer: U.S. Preventive Services Task Force Recommendation Statement,” “Screening for Breast Cancer: An Update for the U.S. Preventive Services Task Force,” and “Effects of Mammography Screening Under Different Screening Schedules: Model Estimates of Potential Benefits and Harms.” They are in the 17 November 2009 issue of Annals of Internal Medicine (volume 151, pages 716-726, pages 727-737, and pages 738-747). The author of the first report is the U.S. Preventive Services Task Force; the authors of the second report are H.D. Nelson, K. Tyne, A. Naik, C. Bougatsos, B.K. Chan, and L. Humphrey; and the authors of the third report are J.S. Mandelblatt, K.A. Cronin, S. Bailey, D.A. Berry, H.J. de Koning, G. Draisma, H. Huang, S.J. Lee, M. Munsell, S.K. Plevritis, P. Ravdin, C.B. Schechter, B. Sigal, M.A. Stoto, N.K. Stout, N.T. van Ravesteyn, J. Venier, M. Zelen, and E.J. Feuer, for the Breast Cancer Working Group of the Cancer Intervention and Surveillance Modeling Network (CISNET).

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